An appreciation of time, some might say an obsession to the fraction of a second, seems to set humans apart from all other species.

The cat presses a needle gently into your face because it's hungry, not because it is 5am.

Despite the subtitle, this book is not about the scientific measurement of time, but about relative time, revealing the regular patterns of people's lives they so often adhere to, unaware, and with no idea why.

Mood swings through the day are surprisingly - even profitably - predictable. Numerous studies have shown mornings and evenings, much more than afternoons, to favour feelings of happiness, warmth towards others, enjoyment and emotional balance. Perceptions of a company's financial report can be more negative if it is released in the afternoon, affecting its share price.

Morning is usually a better time to learn, to solve analytical problems correctly, and, it seems, to hope for a not-guilty verdict. A morning morality effect recognises that many people are likely to be more honest at that time. And if you are thinking of having an accident this afternoon, needing emergency hospital treatment, it would be wise to postpone it until the morning.

Extensive international studies have revealed another pattern that takes a clear dip around the middle, this time the middle of adult life itself. This is not the fabled mid-life crisis, supposed to happen rather earlier, for which the author tells us there is little or no evidence (but look out for middle-aged folk driving red sports cars). It is the pattern of self-assessed happiness, or well-being, which consistently bottoms out in people's early 50s and, surprisingly perhaps, is higher at age 85 than at 18-21.

All these patterns are, of course, broad averages from large population studies and cannot be projected on to any individual. We are assured that the methodological traps in assessing such a nebulous concept as happiness or well-being are well understood and controlled for, but have to be even more trusting when shown the deeply U-shaped curve of the well-being of great apes (as assessed by humans) near their mid-lives.

"We're short of time,'' has been heard on many a planning committee. When? Halfway through the time allotted for the project. Whether a month-long project, half-time in a game, an hour's deadline to produce something, the effect is consistent: the mid-point is a moment of redirection.

Each chapter is followed by a "Time Hacker's Handbook'', an encapsulation of tips and advice the reader might choose to draw upon to guide their own life, the revelations of statistical research. If you had any choice in the matter, placing your name first on a ballot could be advantageous. To win new business, make your pitch before the incumbent supplier makes theirs. Try to be first on the job interview list, provided the list is short.

And the best time to get married with the best omens for it lasting? For fear of misquoting, I will only say: read the book.